1. Field of the Invention
The present invention relates to a capsule endoscope system that guides a capsule endoscope that is introduced into a subject and floats in liquid or is submerged in the liquid in the subject.
2. Description of the Related Art
In recent years, in the field of endoscopy, capsule body-insertable devices (for example, capsule endoscopes) have been proposed that are provided with an imaging function and a wireless communication function and body-insertable device systems have been developed that acquire in-vivo images of a subject by using the capsule endoscope. A capsule endoscope is, for example, swallowed by a patient in order to observe (examine) the inside of the subject. Thereafter, the capsule endoscope moves through the body cavity, such as the internal organs including the stomach and the small intestine, by peristalsis of the internal organs until the capsule endoscope is naturally discharged and functions to capture in-vivo images of the subject at intervals of, for example, 0.5 second.
While the capsule endoscope moves through the inside of the subject, images that are captured by the capsule endoscope are received by an external image display device via antennae that are arranged on the body surface of the subject. The image display device has a function for communicating with the capsule endoscope by wireless communication and an image memory function. The image display device sequentially stores the in-vivo images of the subject, which are received from the capsule endoscope, in a memory. A doctor or a nurse can observe (examine) the inside of the subject and diagnose the subject through display of the in-vivo images of the alimentary canal of the subject.
Japanese Laid-open Patent Publication No. 2005-185544 describes a capsule endoscope that moves using electric propulsion. A living tissue receives a localized electrical stimulus via an electrode. The capsule endoscope moves through a living body using the effects of the contraction of the electrically-stimulated living tissue. The capsule endoscope includes a force sensor that electrically detects whether the electrode, which is provided in the body of the capsule endoscope, and the living tissue have been brought into contact with each other. The capsule endoscope can be stably propelled because a current flows after it is checked, using the force censor, to determine whether the living tissue and the electrode have been brought into contact with each other.